1. Field of the Invention
The invention relates to an optical plug-in connector having optical waveguides held in ferrules for the pluggable connection to a counterplug.
Optical plug-in connectors are needed for the mechanical and optical connection of optical waveguides for an interference-immune transmission of analog and/or digital signals at high data transmission rates in the communications engineering sector.
It is known to connect together optical waveguides having a plug and counterplug, or having an expensive combination of plug-coupling-plug together.
2. Prior Art
U.S. Pat. No. 6,102,581 discloses an optical adapter having ferrules that can be plugged together, in which ferrules for coupling optical waveguides are held in specially manufactured ferrule casings that are in turn plugged together in an adapter casing, it being possible to combine ferrules of different size with one another.
Furthermore, U.S. Pat. No. 5,674,812 describes a mounting for optical plug-in connectors in which two separate optical plug-in connectors are latchably combined in one mounting.
In this connection, in the known optical plug-in connectors, the arrangement of the fiber end sleeves and their mounting in a plug casing have to be matched precisely to one another for correct plugging with minimal signal attenuation, it being necessary to take account of the error tolerances of the plug-in connector casing and also the fiber end sleeves during manufacture.
The object of the invention is therefore to develop an optical plug-in connector of the type mentioned at the outset so as to reduce the error tolerances necessary for a minimum signal attenuation in the arrangement of fiber end sleeves provided with optical waveguides in a plug casing and in a counterplug to a minimum extent.
This object is achieved by a plug-in connector wherein the plug-in connector has a mounting part for at least one optical waveguide held in a ferrule, wherein the ferrule has a reference surface formed by a collar with a defined distance between the reference surface and the end face of the optical waveguide, and wherein, when the plug-in connector is plugged together with a counterplug, the reference surface comes to a stop at a reference surface of a ferrule of the counterplug, and wherein the reference surfaces are fixed in a defined distance.
The advantages achieved by the invention are firstly that the external design and the plug face of the optical plug-in connector comply with the dimensions which have been laid down by the automobile manufacturers in the so-called MOST Co-operation, are compatible with it, but are also capable of being produced more inexpensively and is easier to manipulate during assembly.
A further advantage is in the use of optical waveguides that are provided with ferrules and that have a mechanical coding means for non-interchangeable fitting in the plug-in connector. This eliminates faulty plugging that may result in unserviceability or, under some circumstances, in a destruction of electrical components.
Furthermore, an additional pull relief for the optical waveguides via the casing is unnecessary since the fiber end sleeves are directly crimped onto the fiber and additionally onto the cladding and, consequently, the tensile forces are first convoyed to the ferrules and only then onto the plug-in connector casing. In this connection, the basic principle advantageously applied here of a body of revolution mounted in a casing for mounting an optical waveguide can also readily be extrapolated to similar variants, for example those involving an electrical conductor.
An important advantage is, however, in the direct coupling of the ferrules to one another, the reference surfaces formed by the stop of a collar relative to a defined distance from the end faces of the fiber, the ferrules held in the plug casings, being held axially against one another. In this connection, the ferrules in the counterplug are additionally provided with a compression spring that effects a constant contact pressure of the two ferrules.
Consequently, the dimensional tolerances of the plug casing that normally also enter in addition into the error consideration are eliminated relative to the signal transmission attenuation.
Because of the necessary manufacture of only two components, a mounting part for the optical waveguides provided with ferrules and a casing made by plastic injection moulding technology, an inexpensive manufacture of such optical plug-in connectors is possible.
Advantageously, the ferrules provided with coding means, which are in this case regions projecting from the cylindrical turned part of the sleeve body placed in matchingly designed, negatively shaped chambers of the mounting part in a non-interchangeable manner and held at the same time by the shaping of the chambers in the latter.
It is furthermore advantageous that the mounting part with the inserted ferrules can already be used as plug-in connector, but can also be provided with a casing depending on the field of application.
If an additional casing is used, in the case of assembly or preparation of the plug-in connector, the already advantageously prelatched parts of mounting part and casing are supplied as a single piece and completed solely by insertion of the ferrules provided with optical waveguides and, finally, latched together by further pushing into one another.
Forming two latching plugs arranged at a distance one behind the other on each side of the mounting part first achieves during the assembly a preliminary latching with the latching of the first latching lug into a recess, the two casings thereby first being held loosely together. Only after the second latching lug pair has been latched into the recesses is the mounting part audibly latched to the casing.
A further securing latching is formed in a fold-down manner on the casing. In this connection, this latching is advantageously kept open in its rest position by a hinge mechanism by means of a spring element so that the ferrules can be inserted into the mounting part without difficulty.